The present invention relates to fluid dispensing tool assemblies for evacuating and/or charging a fluid into a fluid system and of the general type disclosed in U.S. Pat. No. 6,298,886 No. RE34,426 and U.S. Pat. No. 4,889,149 which issued to the assignee of the present invention and the disclosures of which are herein incorporated by reference. Such a tool assembly is commonly used to fill or charge fluid systems such as refrigeration and air conditioning systems and motor vehicle coolant, brake fluid, axle fluid and vehicle air conditioning systems. The tool assembly is usually used for first evacuating the system and then charging or filling the system with a predetermined volume of liquid, including a predetermined volume of lubricating oil for a compressor. Since all of the air in the system is removed during the evacuation cycle, the fluid system is filled to a predetermined level without residual air pockets.
It has been determined that it is frequently desirable to have a dispensing tool assembly which is constructed in modular form so that it may be easily manufactured and assembled to dispense only one fluid or multiple fluids such as dispensing lubricating oil and different refrigerants and either with a provision for first evacuating the fluid system or without evacuating the system when a fluid receiving system does not require evacuation. Such a modular system provides for flexibility in the tool assembly and provides for more economical construction of standard components for the dispensing tool assembly. It has also been found desirable for a tool assembly to provide for an optional actuator which is used to open a valve within the fluid receiving system such as an air conditioning or refrigerant system.